Early career

In 1887, at the age of 23,[8] Kook entered his first rabbinical position as rabbi of Zaumel, Lithuania.[2]:p.18[9] In 1888, his wife died, and his father-in-law convinced him to marry her cousin, Raize-Rivka, the daughter of the Aderet's twin brother. Rabbi Kook's only son, Zvi Yehuda Kook, was born in 1891 to Rabbi Kook and his second wife.[10] In 1895, Rav Kook became the rabbi of Bauska.[11][2]:p.22[12]

Between 1901 and 1904, he published three articles which anticipate the philosophy that he later more fully developed in the Land of Israel. Kook personally refrained from eating meat except on the Sabbath and Festivals; and a compilation of extracts from his writing, compiled by his disciple David Cohen, known as "Rav HaNazir" (or "the Nazir of Jerusalem")[13] and titled by him "A Vision of Vegetarianism and Peace," depicts a progression, guided by Torah law, towards a vegetarian society.[14][15]

Jaffa

In 1904,[16] Rav Kook moved to Ottoman Palestine to assume the rabbinical post in Jaffa (Yafo), which also included responsibility for the new mostly secular Zionist agricultural settlements nearby. During these years he wrote a number of works, most published posthumously, most notably a lengthy commentary on the Aggadot of TractatesBerakhot and Shabbat, titled Eyn Ayah, and a brief book on morality and spirituality, titled Mussar Avicha.
Another book, a collection of his letters called Igrot Hareiyah, incorporated the acronym of his name, Abraham Isaac.

It was in 1911 that Rav Kook also maintained a correspondence with the Jews of Yemen, addressing some twenty-six questions to "the honorable shepherds of God's congregation" (Heb. כבוד רועי עדת ד) and sending his letter via the known Zionist emissary, Shemuel Yavneʼeli. Their reply was later printed in a book published by Yavneʼeli.[17][18] Rav Kook's influence on people in different walks of life was already noticeable, as he engaged in kiruv ("Jewish outreach"), thereby creating a greater role for Torah and Halakha in the life of the city and the nearby settlements. In 1913 Rav Kook led a delegation of rabbis, including several leading rabbinic figures such as Rabbi Yosef Chaim Sonnenfeld, to the many newly established secular "moshavot" (settlements) in Samaria and Galilee. Known as the "Journey of the Rabbis" the rabbis' goal was to strengthen Shabbat observance, Torah education, and other religious observances, with an emphasis on the giving of 'terumot and ma'asrot' (agricultural tithes) as these were farming settlements.[19]

Chief Rabbi of Jerusalem

In 1924, Rav Kook founded a yeshiva, Mercaz HaRav Kook (popularly known as "Mercaz HaRav"), in Jerusalem. Rav Kook decided to name the Yeshiva "Mercaz HaRav" to represent his vision of the Yeshiva being a place where the "Rav," or "many", could come to learn from all corners of the World.

Rav Kook was a master of Halakha in the strictest sense, while at the same time possessing an unusual openness to new ideas. This drew many religious and nonreligious people to him, but also led to widespread misunderstanding of his ideas. He wrote prolifically on both Halakha and Jewish thought, and his books and personality continued to influence many even after his death in Jerusalem in 1935, reflected in attendance of his funeral by an estimated 20,000 mourners.[22]

Letter In The Name of The Chofetz Chaim In Honor and Support of Rav Kook

Rabbinic Proclamation In Honor and Support of Rav Kook

Rav Kook Letter Regarding Entering Har Habayit

Proclamation of Rav Kook Regarding The Importance of Shemittah Observance

Proclamation of Rav Kook Regarding Elections

Letter of Rav Hutner to Rav Kook

Letter of Rav Avraham Dov-Ber Shapiro to Rav Kook

Letter of Rav Nosson Zvi Finkel To Rav Kook

Letter of Rav Bengis To Rav Kook

Letter of Rav Shmuel Salant and Rav Chaim Berlin To Rav Kook

Rav Kook tried to build and maintain channels of communication and political alliances between the various Jewish sectors, including the secular Jewish Zionist leadership, the Religious Zionists, and more traditional non-Zionist Orthodox Jews. He believed that the modern movement to re-establish a Jewish state in the land of Israel had profound theological significance and that the Zionists were agents in a heavenly plan to bring about the messianic era. Per this ideology, the youthful, secular and even anti-religiousLabor Zionist pioneers, halutzim, were a part of a grand Divine process whereby the land and people of Israel were finally being redeemed from the 2,000-year exile (galut) by all manner of Jews who sacrificed themselves for the cause of building up the physical land, as laying the groundwork for the ultimate spiritual messianic redemption of world Jewry.

Inauguration of Hebrew University

In 1928, Rav Kook wrote a letter to Rav Yosef Messas (Chief Rabbi in Algeria), addressing certain misquotes which were erroneously being repeated in his name regarding a speech he gave at the inauguration of Hebrew University. The following are translated excerpts from the letter Rav Kook wrote to Rav Messas:

...from the time that I came to the Holy Land, it has been my goal to the best of my ability to draw also those who are estranged and speak to their heart, so that they will come close to Torah and mitzvot – including even those young people who want to develop their physical health so that they will have the strength to protect our holy nation in times of violence, Heaven forbid, at a time when vicious enemies rise up against us...in regard to Hebrew University, Heaven forbid that I should say regarding secular studies that 'From Zion will come forth Torah.'

To the contrary, I told them explicitly that I am afraid lest there come forth, Heaven forbid, a stumbling block from their hands if they reject the Torah and the fear of G-d and 'please themselves in the brood of aliens' [i.e., studies antithetical to Torah such as Biblical Criticism]. I brought them examples of this from the past, from the incidents that took place due to people’s sins [during the Berlin Enlightenment], from which came forth groups that turned away from G-d and abandoned the source of living waters. But they must guard the holiness of Israel, teachers and students alike, and not follow foreign ideas nor turn aside from the Torah and the mitzvos. And even then, it is not from secular subjects that Torah will come forth, but rather when we support the holy yeshivas, which are dedicated solely to the holiness of the Torah.

Together with this, [I told them that] they should elevate the power of the tzaddikim and Torah giants who fear G-d. And the Central Yeshiva [Mercaz HaRav] in our holy and beautiful city, which we are toiling to establish and expand with G-d’s help, will stand in its great glory. Then, upon the foundation of the holy yeshivas, I said that the verse 'From Zion will come forth Torah' will be fulfilled.

These words are explicit in my speech that I spoke at that time before the people, before all of the important officials who came to the celebration, and to the entire great crowd of thousands who came from the far ends of the Holy Land and from the lands of the Diaspora. So how can malicious people come to distort the words of the living G-d in a way that is so filled with wickedness and folly?...

Theodor Herzl eulogy

In 1904, Rav Kook wrote a letter to his father-in-law, Rabbi Eliyahu David Rabinowitz-Teomim (also known by the acronym "The Aderet"), addressing certain misquotes which were erroneously being repeated in his name regarding a speech he gave after Theodor Herzl's passing. The following are translated excerpts from the letter Rav Kook wrote to Rav Rabinowitz-Teomim:

...Now, two gentlemen came to me… and requested me … since they were planning to gather in the bank building here to honor the memory of Dr. Herzl and it was their finding that even those opposed to Zionism would not deny that there were in his heart thoughts concerning the betterment of Israel. Although unfortunately [Herzl] did not find the straight path, nevertheless, 'The Holy One does not withhold credit for even good talk.' It would be poor manners not to arrange a memorial in his honor in a public meeting place, such as the Anglo-Palestine Bank here. Therefore I promised them I would attend.

Understandably, once I agreed to come, I did not want to refuse to speak some words. I assessed that, God willing, benefit would derive from my words, inasmuch as the other speakers would not have the audacity to belittle God, His Torah, and the sages of Israel.

Thank God, this assessment proved correct. Of course, I spoke pleasantly and politely, but I did reveal the fundamental failure of their [the Zionists’] entire enterprise, namely the fact that they do not place at the top of their list of priorities the sanctity of God and His great name, which is the power that enables Israel to survive ... In my remarks, I offered no homage to Dr. Herzl per se.

What I did say was that such a thought of improving the situation of Israel in Eretz Israel would be worthwhile if we would rise to the occasion. It would require return to G-d by observing and honoring the Torah, and a consensus that the foundation of all must be the power of Torah. Repenting of baseless hatred, and wholehearted peace-seeking as obligated [by Torah] would result in success because it would be close to G-d’s will. We must make amends toward the future that the power of the sanctity of Torah be at the top of our list of priorities, that "the son of Yishai lead." If the will to improve materially will rest on Torah – then God will shine His face upon us and crown our every deed with success. At first, the salvation will be gradual, as our holy Rabbis remarked upon witnessing daybreak over the valley of Arbel, but after it will gain momentum, appearing as a great and wondrous light, as in the days of our Exodus from Egypt.

After [the address], others came to me and reported that some people read into my words ideas that I never intended ...

His empathy towards the non-religious elements aroused the suspicions of many opponents,[23] particularly that of the traditional rabbinical establishment that had functioned from the time of Turkey's control of greater Palestine, whose paramount leader was Rabbi Yosef Chaim Sonnenfeld. However, Rav Yosef Chaim Sonnenfeld and Rav Kook deeply revered each other, which is evidenced by their respectful way of addressing each other, and the honor which they showed each other (as recorded in photos).

Rav Kook remarked that he was fully capable of rejecting, but since there were enough practicing rejection, he preferred to fill the role of one who embraces. However, Rav Kook was critical of the secularists on certain occasions when they violated Halacha (Jewish law), for instance, by not observing the Sabbath or kosher laws, or ascending the Temple Mount.

Rav Kook wrote rulings presenting his strong opposition to people ascending the Temple Mount, due to the Jewish Laws of impurity. He felt that Jews should wait until the coming of the Messiah, when it will be encouraged to enter the Temple Mount. However, he was very careful to express the fact that the Kotel and the Temple Mount were holy sites that belong to the Jewish people.

Rav Kook also opposed the secular spirit of the Hatikvah anthem, and penned another anthem with a more religious theme entitled haEmunah.

Legacy

While Rabbi Kook is exalted as one of the most important thinkers in mainstream Religious Zionism, there are several prominent quotes in which Rav Kook is quite critical of the more modern-orthodox Religious Zionists (Mizrachi), whom he saw in some ways as naive and perhaps hypocritical in attempting to synthesize traditional Judaism with a modern and largely secular ideology.
Rav Kook never shied away from gently offering constructive criticism to his peers, religious and secular. Rav Kook was interested in outreach and cooperation between different groups and types of Jews, and saw both the good and bad in each of them. His sympathy for them as fellow Jews and desire for Jewish unity should not be misinterpreted as any inherent endorsement of all their ideas. That said, Rav Kook's willingness to engage in joint-projects (for instance, his participation in the Chief Rabbinate) with the secular Zionist leadership must be seen as differentiating him from many of his traditionalist peers. In terms of practical results, it would not be incorrect to characterize Kook as being a Zionist, if one defines a Zionist as one who believes in the re-establishment of the Jewish people as a nation in their ancestral homeland. Unlike other Zionist leaders, however, Kook's motivations were purely based on Jewish law and Biblical prophecy.[citation needed]

The IsraelimoshavKfar Haroeh, a settlement founded in 1933, was named after Rav Kook, "Haroah" being a Hebrew acronym for "HaRav Avraham HaCohen". His son Zvi Yehuda Kook, who was also his most prominent student, took over teaching duties at Mercaz HaRav after his death, and dedicated his life to disseminating his father's writings. Many students of Rav Kook's writings and philosophy eventually formed HardalReligious Zionist movement which is today led by rabbis who studied under Rav Kook's son at Mercaz HaRav.

Support from rabbinic scholars

With the sudden public display of rare letters from the greatest Jewish scholars to Rav Kook, many questions have emerged. Rav Kook wrote that he was not part of any party – he simply viewed himself as a follower of God and the laws of the Torah. His relationship with many different types of leaders and laymen, was a part of his general worldview – that all Jews must work together in serving God and bringing the redemption. Also, one could see from the published letters, that the "Chareidi" leadership was firm in its support of Rav Kook, and in fact had an apparent fond relationship with him. The vast majority of the "Chareidi" leaders publicized handwritten letters in support of Rav Kook, when a few individuals were publicly disrespectful towards him. Rav Kook embraced the support, but made clear that any insults were accepted by him without anger, for he viewed himself "as a servant of G-d," without interest in his personal honor.

Some examples of greetings in letters written by Jewish leaders to Rav Kook:

Rav Boruch Ber Leibowitz: "The true gaon, the beauty and glory of the generation, the tzaddik, his holiness, Rabbi Avraham Yitzchak, may his light shine, may he live for length of good days and years amen, the righteous cohen, head of the beis din [court] in Jerusalem, the holy city, may it soon be built and established"

Rav Yosef Yitzchok Schneersohn of Lubavitch: "The Gaon who is renowned with splendor among the Geonim of Ya’akov, Amud HaYemini, Patish HaChazak..."

Rav Chatzkel Abramsky: "The honored man, beloved of Hashem and his nation, the rabbi, the gaon, great and well-known, with breadth of knowledge, the glory of the generation, etc., etc., our master Rabbi Avraham Yitzchak Hacohen Kook, shlita, Chief Rabbi of the Land of Israel and the head of the Beis Din in the holy city of Jerusalem"

Rabbi Gideon Weitzman, Light of Redemption: A Passover Haggadah Based on the Writings of Rav Kook, Urim Publications. ISBN978-965-7108-71-0.

Also there is now a musical project that presents Rav Kook's poetry with musical accompaniment.
HA'OROT-THE LIGHTS OF RAV KOOK by Greg Wall's Later Prophets Featuring Rabbi Itzchak Marmorstein – released on Tzadik Records, April 2009.[29][30][31]

Quotes

Therefore, the pure righteous do not complain of the dark, but increase the light; they do not complain of evil, but increase justice; they do not complain of heresy, but increase faith; they do not complain of ignorance, but increase wisdom.[32]

There could be a freeman with the spirit of the slave, and there could be a slave with a spirit full of freedom; whoever is faithful to himself – he is a freeman, and whoever fills his life only with what is good and beautiful in the eyes of others – he is a slave.[33]

Gallery

Funeral of Rav Kook, Jerusalem 1935

Rav Kook and Rav Sonnenfeld

Rav Kook and Rav Frank

Letter of Rav Boruch Ber Leibowitz About Rav Kook

Letter of Rav Chaim Ozer Grodzinsky About Rav Kook

Badatz Eidah Chareidis writing In support and Defense of Rav Kook

Main entrance of Beit HaRav (Rav Kook's House) in Jerusalem, Israel

Stone carving above door where Rav Kook lived when he was the Chief Rabbi in the 1920s and 30s.

Interior view of the part of Beit HaRav used for Yeshiva Mercaz HaRav as well as synagogue.

^"After serving as rabbi in the small town of Zoimel and later in the city of Boisk (Bauska), Latvia, in 1904 Rabbi Kook accepted
the invitation of the port city of Jaffa ...""Rav Kook - Orot". orot.com.

^Jewish Affairs, in Report by His Majesty's Government in the United Kingdom of Great Britain and Northern Ireland to the Council of the League of Nations on the Administration of Palestine and Trans-Jordan for the year 1935 by His Majesty's Government in the United Kingdom of Great Britain and Northern Ireland to the Council of the League of Nations on the administration of Palestine and Trans-Jordan for the year 1935, The Office of High Commissioner for Palestine and Trans-Jordan, Jerusalem, 1935

^Morrison, Chanan (2006). Gold from the Land of Israel: A New Light on the Weekly Torah Portion - From the Writings of Rabbi Abraham Isaac HaKohen Kook'. Urim Publications. pp. 353–356. ISBN965-7108-92-6.